Real-time Performance Control of Elastic Virtualized Network Functions

Transcription

1 Real-time Performance Control of Elastic Virtualized Network Functions Tommaso Cucinotta Bell Laboratories, Alcatel-Lucent Dublin, Ireland

2 Introduction

3 Introduction A new era of computing for ICT Wide availability of broadband connections ==> shift in computing paradigms towards distributed computing (cloud computing) More and more resources provided remotely Not only remote storage and batch processing But also remote processing for interactive applications Network operators are shifting provisioning of critical network services to virtualized network functions (through private or hybrid cloud provisioning models) Examples Virtual Reality with heavyweight physics simulations Distributed editing of HD video (film post-production) 3

4

5

6

7

8

9 Co-Scheduling Virtual Machines Issues in deploying RT SW in VMs Scheduling and timing VM scheduling impacts on the vision of time by guest OSes SMP-enabled guests Time granularity (for measuring time and setting timers) Non-uniform progress-rate of applications Spin-lock primitives assume release of locks within very short time-frames What happens if the lock-owner VM is descheduled? Benchmarking A VM may be deployed on different HW (SOA scenario) How to achieve predictable performance? VMs may be deployed on General-Purpose HW (with cache) How to account for HW-level interferences? 9

10 Co-Scheduling Virtual Machines Issues in deploying RT SW Components in VMs Temporal isolation across VMs Compute-bound and I/O-bound VMs Shared host resources (e.g., network interrupt drivers) Intensive I/O on virtualised peripherals (big-data) Proper management of shared resources: what MP resource-sharing protocol is appropriate? Proper management of priority inversion Reduced overheads (limited number of preemptions) Run-time schedulability analysis and admission control 10

11

12 Possible Solutions Another approach Let multiple VMs use the same resources Use proper resource scheduling strategies For example Computing Xen credit-based, SEDF schedulers, RT-Xen exts Networking QoS-aware protocols (IntServ, MPLS) Advantages Increased flexibility Increased resource saturation levels Reduced infrastructure costs

13 General IRMOS Approach

14

15 Approach Traditional (hard) real-time techniques are not appropriate lead to poor resource utilization imply high/unsustainable development costs Soft real-time techniques are more appropriate Stochastic models for system/qos evolution Probabilistic guarantees (as opposed to deterministic ones) Pragmatic approach Theory is always applied on real GPOS (Linux) with a real Virtual Machine Monitor (KVM) on real multimedia applications (mplayer, vlc,...) 15

16 Approach Basic Building blocks Linux / KVM enriched with our RT Scheduler(s) Each VMU is attached RT scheduling parameters (defining its temporal capsule) Improvements on the real-time virtualization performance Modifications at the hypervisor level Modifications at the kernel level Analysis of Virtualized RT applications by Hierarchical Real-Time Schedulability Analysis 16

17 U=~25% 17 TM AT THE SPEED OF IDEAS 17

18 U=~50% 18 TM AT THE SPEED OF IDEAS 18

19 U=~50% 19 TM AT THE SPEED OF IDEAS 19

20 Experimental Results (application-level benchmark) Download time for a 100 KB file from Apache Periodic download requests every 20ms Response-times may be kept much more stable by real-time scheduling

21 Controlling Elastic Virtualized Applications

22 Plethora of Cloud Providers, Tools and Frameworks Cloud IaaS Amazon, Rackspace, Google Compute,... OpenNebula, OpenStack, CloudStack CloudBand,... Configuration Management (skip) Monitoring and Orchestration Amazon AutoScaling, Heat+Ceilometer, Cloudify, CloudFoundry, Chef Recipes,...

23 Elasticity Loop VM VM QoS QoS Reqs Reqs LB LB Controller Controller VM VM SLA Elastic Elastic Component Component System or Application Metrics

24 But... Adaptation logic built on unstable terrain!

25 But... Adaptation logic built on unstable terrain! Can we make anything better?

26 Related Publications Elastic Admission Control for Federated Cloud Services, (to appear on) IEEE Transactions on Cloud Computing "Data Centre Optimisation Enhanced by Software Defined Networking," (to appear) in IEEE CLOUD 2014 "Brokering SLAs for end-to-end QoS in Cloud Computing," CLOSER 2014, Barcelona "End-to-End Service Quality for Cloud Applications," GECON 2013, Zaragoza "Run-time Support for Real-Time Multimedia in the Cloud," REACTION 2013, Vancouver "Admission Control for Elastic Cloud Services," IEEE CLOUD 2012, Hawaii "Virtualised e-learning with Real-Time Guarantees on the IRMOS Platform," IEEE SOCA, December 2010 [best paper award] "Hierarchical Multiprocessor CPU Reservations for the Linux Kernel, OSPERT 2009, Dublin

27 Thanks for your attention Questions? 27